Yogurt can be a wonderfully healthy food. But check the ingredients to make sure the yogurt brand in your hand has just yogurt in the container!
Real yogurt doesn't need gelatin, pectin, tapioca, or guar gum. Real yogurt has made the transition from milk to thick, predigested dairy product through the action of one or more types of bacteria that ferment milk sugar (lactose) to lactic acid and cause the milk to thicken.
The conversion of lactose to lactic acid means that those who are lactose-intolerant can enjoy yogurt.
Real yogurt is sour, so the tendency in America is to sweeten it, usually with sugar or an artificial sweetener. Around the world, though, yogurt is eaten unsugared. I will add home-tested recipes for these foods here from time to time. When shopping for yogurt, check the ingredients to make sure it is unsugared.
Real yogurt also contains live bacteria. The milk the yogurt is made from will have been pasteurized, but the yogurt should not have been pasteurized after fermentation, or the good bacteria in it will have been killed. Because of wide-spread interest in yogurt as a healthy food, most brands no longer kill off the good bacteria through pasteurization but brag proudly on the label that they the product contains live bacteria. This is what we're looking for!
In our local farmers' market, we can buy local yogurt from two vendors. Both are whole-milk, unsugared, unadulterated yogurt, one 'greek' (extra-thick) and one regular consistency. In years past, a goat yogurt has also been available - I'll have to check to see if that vendor still provides it on a regular basis.
Yogurt has a good effect on digestion for many people. As a fermented product, it is inhabited by beneficial bacteria and pre-digested by them. You might want to read this Wikipedia article on Yogurt for more information.
A useful book on the value of fermentation and the pre-digesting of foods has been written by Sandor Ellix Katz. It is called Wild Fermentation. Yogurt is just one of a multitude of beneficial fermented foods he talks about.